Wheel size - VDO computer

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a
26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08
computer" the same wheel size 2133 mm (84.0").

The wheel size indicated for the MTB in the manual is actualy 26x2.125
(mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler
taking into account the data the manufacturer of the tire gives?

Than you

Peter


--
Peter_49

Dear Peter: Sheldon has done a masterful job of answering this question at:
http://www.sheldonbrown.com/cyclecom...libration.html

Dave Reckoning

"Peter_49" wrote in message
...

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a
26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08
computer" the same wheel size 2133 mm (84.0").

The wheel size indicated for the MTB in the manual is actualy 26x2.125
(mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler
taking into account the data the manufacturer of the tire gives?

Than you

Peter


--
Peter_49

Dear Peter: Sheldon has done a masterful job of answering this question at:
http://www.sheldonbrown.com/cyclecom...libration.html

Dave Reckoning

"Peter_49" wrote in message
...

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a
26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08
computer" the same wheel size 2133 mm (84.0").

The wheel size indicated for the MTB in the manual is actualy 26x2.125
(mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler
taking into account the data the manufacturer of the tire gives?

Than you

Peter


--
Peter_49

Peter_49 wrote:

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

It's not a mistake. "700x23c" is the most common tyre size for road bikes,
which is actually a 23-millimeter tyre on a 622-millimeter rim. "26x2.1"
is a common size for mountain bikes which use 26-inch wheels - 2.1 is
the width of the tyre in inches. The rim is actually 559 millimeters in
diameter and the tyre about 53 millimeters.

So what you have is a big wheel with a skinny tyre and a smaller
wheel with a fat tyre, and the total circumference is indeed almost the
same.

However, the actual value for the 700x23c tyre in the VDO manual isn't
very accurate. A 23-millimeter tyre for a road bike is almost never 2133
millimeters in circumference, but usually somewhere between 2090 and
2100 millimeters.

-as

Peter_49 wrote:

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

It's not a mistake. "700x23c" is the most common tyre size for road bikes,
which is actually a 23-millimeter tyre on a 622-millimeter rim. "26x2.1"
is a common size for mountain bikes which use 26-inch wheels - 2.1 is
the width of the tyre in inches. The rim is actually 559 millimeters in
diameter and the tyre about 53 millimeters.

So what you have is a big wheel with a skinny tyre and a smaller
wheel with a fat tyre, and the total circumference is indeed almost the
same.

However, the actual value for the 700x23c tyre in the VDO manual isn't
very accurate. A 23-millimeter tyre for a road bike is almost never 2133
millimeters in circumference, but usually somewhere between 2090 and
2100 millimeters.

-as